This project is both a wartime biography and an examination of the American effort in France during the First World War. At its core, the narrative follows the military career of Major General James G. Harbord. His time in France saw Harbord serve in the three main areas of the American Expeditionary Forces: administration, combat, and logistics. As chief of staff to AEF commander General John J. Pershing, Harbord was at the center of the formation of the AEF and the development of its administrative policies. He organized and managed the AEF General Staff and served as Pershing's most trusted subordinate. In May of 1918, Harbord transferred to the fighting line, taking over command of the 4th "Marine" Brigade. During his time with the 4th Brigade, and later as commander of the 2nd Division, Harbord played a significant part in the battles of Belleau Wood and Soissons. A dedicated supporter of Pershing's tactics of "open" warfare, Harbord's failings as a combat commander showed the limits of American tactical experience. For the final four months of the war, Harbord took over control of the AEF's logistical system, the Services of Supply. Though he proved an able administrator, the American supply system approached total collapse in the fall of 1918, and was prevented only by the signing of the Armistice. In all three of these roles, Harbord embodied the emergence of the military manager in the American army. The First World War illustrates that war had grown so large and complex that it required officers whose primary talents lay not in leading men in combat, but in the areas of administration and management of large bureaucratic organizations. James Harbord was one of the first, and best, examples of this new type of officer.